1. Field of the Invention
The present invention relates to a method and apparatus for obtaining a scalable and managed bandwidth for connections between asynchronous level and synchronous hierarchical level in a telecommunication network.
2. Description of the Prior Art
As it is known to those working in the telecommunications field, there is a more and more emerging need for best interconnection among the nodes of a telecommunication network.
More particularly, two alternative approaches are known: in a first known type, the nodes of a packet data network, e.g. IP (Internet Protocol), can be directly interconnected by using communication procedures involving the packet data level only; in a second known type, the network nodes can be interconnected by using the transport capacity of a synchronous digital hierarchy network, e.g. SDH or SONET.
Within the framework of the second type of approach, the major technical problem to be solved is that of ensuring the best flexibility in the use of the available transport bandwidth of the synchronous digital network, as far as the badwidth demand increases with the traffic volume of packet data to be transported.
A known technique for solving this problem is to use the so-called concatenation of virtual containers, namely to arrange the packet flow in a number of concatenated lower-order virtual containers in the frame of the synchronous hierarchy network, so as to get a more complex frame structure carrying all the packets.
A drawback of this technique is that the concatenation functionality is not available at all the network nodes.
Another known technique is to use an higher-order virtual container, e.g. VC3 or VC4, according to the standard synchronous hierarchy.
However this second technique has the drawback that a too high bandwidth is requested to fully comply with the synchronous hierarchical structure, with a considerable waste of bandwith due to the fact that generally a part of the higher-order virtual containers is not used.